Pnettmatically-operated controller



F E. CASE. PNEUMATICALLY OPERATED CONTROLLER.

APPLICATION FILED JULY 10. l9l8.

1,326,025. Patented Dec. 23,1919.

2 SHEETSSHEET I.

H I I I I I M I L Figl.

'WUPlr- 07? R I T Inventor" PanK E3. Case, by fl His At o1-n e F. E. CASE. PNEUMATICALLY OPERAIED CONTROLLER. APPLICATION FILED JULY 10. 1918.

1,326,025. I Patented Dec. 23, 1919.

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|-Iis Att ovnegr new and useful Improvements UNITED STATES PATENT OFFICE.

FRANK E. CASE, OF vSGHENECTADY, NEW YORK, ASSIGNOR TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

PNEUMATICALLY-OPERATED CONTROLLER.

To all whom it may concern:

Be it known that I, FRANK E. CAsn, a citizen of the United States, residing at Schenectady, in the county of Schenectady, State of New York, have invented certain in Pneumatically- Operated Controllers, of which the following is a specification.

This invention relates to the control of electric motors and has for its object the provision of improved means whereby electric motors are started, stopped and generally controlled in a simple, reliable and efficient manner. a

While my invention is capable of general application to the motor control field, it is of particular importance in the control of electric railway motors.

In carrying out my invention I provide an improved electropneumatic device which operates to effect a step-by-step control for the motor or motors. This device comprises a main piston which operates the controlling member and an auxiliary piston which operates alternately with the main piston .to give an intermittent action to the main'piston. When the main piston moves forward a predetermined amount it automatically relieves the pressure upon its working surface and transfers the pressure to the auxiL iary piston which thereupon moves forward the same distance. At the end of this step the pressure is again transferred .to the main piston which again moves forward a step. The action of the auxiliary piston is retarded so that a perceptible interval elapses between successive movements of the main piston. The movement is also under the control of the motor current so that the controlling element cannot operate until the motor current drops to the proper value. Other features of my invention will appear in the course of the following specification in which I have shown my invention em-' bodied inv concrete form for purposes of illustration.

In the accompanying drawing illustrating my invention Figure 1 is a diagrammatic view of the motor and control circuits; Fig. 2 a sectional view of'a pneumatic engine; Fig. 3 is a detailed view of the retarding device; Fig. 4 is a diagrammatic view of the connections for the motor circuits; and

Specification of Letters Patent.

Patented Dec. 23, 1919.

Application filed July 10. 1918. Serial No. 244.163.

Fig. 5 shows a detail of valve arrangement.

Referring to the drawing, I shall first describe the pneumatic engine, shown in Figs. 2 and 3. It will be noted that there are two cylinders 10 and 11 to which air pressure is admitted through ports'12 and 13. In each of these cylinders are two pistons 14 and 15, 16 and 17. 15 and 16 are the mam pistons for operating the controlling element and are rigidl connected together by a rack 18, while pistons 14. and 17 are the auxiliary pistons, likewise rigidly connected together by a rack 19. The rack 18 is in the form of a rod which is U shaped in cross section so as to receive the rod upon which the rack 19 is formed. The arrangement of the two pairs of pistons is the same, so that it will only be necessary to describe one of them. As shown, both pistons are provided with valve openings 20 and 21 for to the air pressure in the cylinder, that the valve 23 will first close the opening in the piston 15, and upon further movement, the valve 22 will move off its seat and open a passage through the piston 14. -\Vhen the valve 22 is opened it is held open by spring 23. The rack 19 is connected by reduction gearing 25 with a retarding device 26 which I have shown in Fig. 2 as a'magnetic friction device, in which two brake shoes 27 and 28, pivoted at 29 are pressed against the inner surface of" a cup shaped magnetic member 30 by centrifugal force against the action of springs 31. This permits the piston 14 to move forward slowly. This retarding device is likewise controlled by an electromagnet winding 32 which positlvely holds the piston against-movement when the winding is energized. In Fig. 3 this retarding device is shown in section as consisting of a winding 32 which causes a magnetic attraction between the cup shaped magnetic member 30 and the magneticshoes 27 and 28 secured to the shaft 34 and driven by the gear 25 and pinion 3,5. In like manner the piston 15 will move forward when the passage through the piston 14 is open. The piston 15 will move until the lost mot on 1s taken up whereupon the valve 22 will be closed and the valve 23 opened thereby stopping the movement of the main P15130121. lVhen valve 23 opens, the spring 23 holds it open. The rack 18 drives a gear 36, which in turn drives a shaft upon which the cams are mounted, only one of which (37) is shown in the drawing. These cams operate unit switches, one of which is shown at 38. The particular arrangement of the cams for operating the unit switches, and the structure of the latter, form no part of my invention, and need no further description since they are fully described in my previous Patent No. 1,221,676, dated April 3, 1917.

The admission of air to the cylinders 10 and 11, and hence the operation of the pistons, is controlled by two electro-magnetically operated valves 39 and 40. The valve 39 is normally closed to the reservoir and open to atmosphere, so that the energization of its winding opens this valve and connects the cylinder with the reservoir and closes the cylinder to atmosphere. The valve. 40 is normally opened to reservoir and closed to atmosphere, so that the energization of its winding closes the cylinder 10 and opens the connection of the cylinder to atmosphere. Mounted above the cylinders is a reversing switch controlled by two electro-. magnetic switches 41, and 42. The arrangement of this reversing switch is identical with that described in my previous patent above referred to and requires no further description herein, except to state that the energization of one of the electromagnetic valves throws thereversing drum 43 so as to make one set of connections while the energization of the other electromagnetic valve throws the reversing drum so as to make the opposite set of connections.

The operation .of the pneumatic engine will now be clearly understood. If, for instance, the forward operation of the controller is desired, the magnetic windings of both electromagnetic valves 39 and 40 will be energized. This will open the valve 39 and admit air pressure to the piston 17 and also operate the valve 40 to cut off the reservoir and open the cylinder 10 to atmosphere. The pressure on the piston 17 causes it to move forward while the piston 16 reniains stationary. The forward movement of the piston 17 merely drives the retarding device 26 through the gearing 25 so that this movement will be retarded or when the winding 32 is energized as hereinafter described it will be positively stopped until the motor current drops to the proper value. When the piston 17 moves forward slightly the conical end of the valve which connects the two pistons closes the opening through the piston 16 and through the lost motion connection the piston 17 moves farther until the lost motion is taken up whereupon the piston moves away from the conical end 22 of the valve thereby opening apassage through the piston 17. This permits the pressure to act upon the piston 16 which in turn moves forward and drives the gear 36 to turn the cam shaft. As the piston 17 moves forward the opening of the piston 17 will be closed and the opening of the piston 16 will once more open. This movement will be repeated, and each movement of the piston 16 will turn the cam shaft one step, while eachmovement of the piston 17 operates the retarding device this movement will be continuedto the end of the stroke if the magnetic windings of both valves 39 and 40 are left energized. Upon the denergization of these two valve windings, pressure will be admitted to the cylinder 10 and cylinder 11 will be connectall the parts are in the position which they assume when all circuits are deenerg'ized. Assuming now that it is desired to start the motors, the switches 44 and 45 will first be closed, the latter being closed at its left hand contact. The closure of the switch 44 energizes the potential relay B from the trolley T through the winding of the relay B to ground. If now the master controller MO is moved toward the left to the first forward position the reversing switch will be operated by the energization of the electromagnetic valve 42 in-case thereverser should be in the wrong position. As shown, however, the reverser has been left in the forward position so that there is no change with reference to this switch. The line breaker LB now closes, being energized from the battery and the contacts 46 of the master controller through the reversing switch RS, upper interlocks on overload relay 0. R., contacts of the potential relay B, through the winding of the line breaker, thence across the bridging contact 47 on the controller drum and back to the battery. The closing of the line breaker does not'close the motor circuit but energizes the windings of the electro-magnetic valves 39 and 40, the circuit being from the battery, across contacts 48 of the controller, interlocking contact 49 of the line breaker, through the two windings of the valves 39 and 40 thereof and back to battery through conductor 49. -The energization of the two magnetic valves 39 and 40 operate the cam shaft, as above-pointed out, one step to close the contact'50 thereby completlng the motor circuit as follows from the trolley T, through the overload relay 0' R. through the contacts 51 of the line breaker, through the resistance B, through thereby bringing the motors up the reversingswitch, armature A, field windings .F, F, resistance sections R R through the contacts 50, through the resistance sections R R through the field windings F and F thence through the reversing switch, armature A through the current limit relay o'r throttle D to ground. The windings 39 and 40 being energized, the controller will move forward step y step. In passing from the first to the second step the contactor 52 will be energized at contact 53 thereby cutting out the section of resisance B. When the position 6' of the controller is reached the motors will be in parallel, and when the final step 2' is reached the motors will be in full parallel with 1 all the resistance cut out of circuit and field windings F and F cut out, to full speed.

It will be noted that the winding 32 of the retarding device is energized through the contacts G on the controller and through the contacts of the current limit relay or throttle D. When the current is above the proper value the winding 32 will, therefore, be energized to stop the movement of the controller providing the latter is not be tween two positions but has made a complete step and is in one of its definite positions. It will be noted that the contacts G are at the positions a, b, c, d, etc., and-that when the controller moves out of one of these positions the contacts G are no longer effective. The result of this arrangement is that when the controller starts to take a step, it-will complete the step regardless of the closing of the throttle due "to increase in current. The system in general operates in a manner similar to that disclosed in my earlier patent above referred to and therefore requires no further description.

While I have described my invention as embodied in concrete form and as operating in a specific manner in accordance with the provisions of the patent statutes, it should be understood thatI do not limit my invention thereto as various modifications thereof will suggest themselves to those skilled in the art without departing from the spirit of my invention the .scope of which is set forth in the annexed claims. i

What I claim as new and desire to secure by Letters Patept of the United States, is

V 1. The combination with 'a controller for 'motor circuits of a fluid motor for operating said controller step by step comprising a cylinder and two pistons, and valve mechanism operated by the pistons to cause the pistons to execute successive intermittent movements in the same direction,

2. The combination with a controller for motor circuits of means for operating said a controller step by step comprising pistons arranged to execute successive intermittent movements in the same direction, a controlling member driven by one of said plstonsI and means for applying pressure to said pistons.

3. The combination with a controller for motor circuits of means for operating said controller step by step comprising a cylinder, a piston therein for driving the controller and means whereby a slight movement of the piston relieves the pressure thereon for an interval causing it to temporarily stop and means for applying pressure to said pistons.

4. The combination'with a controller for motor circuits of means for operating said controller step by step comprising a cylinder, two pistons therein one of which drives the controller means whereby a slight movement of each piston causes the pressure to be transferred to the other piston and means for applying pressure to said pistons.

5. The combination with a controller for motor circuits of means for operating said controller step by step comprising a cylinder, two pistons controller, adevice associated with the other piston for temporarily stopping the same, means whereby a slight movement of each piston causesthe pressure to be transferred to the other piston and means for applying pressure tothe pistons.

6. The combination with a controller for motor circuits of means for operating said controller step y step comprising a cylinder, two pistons therein one of which drives the controller, a stopping device controlled therein one of which drives the i by the motor current associated with the other piston, means whereby a slight move ment of each piston causes the pressureto be transferred to the other piston and means for applying pressure to the pistons.

7. The combination with a controller for motor circuits of means for operating said controller step by step in both directions comprising a cylinder ,for each direction of movement, two pistons in each cylinder, means whereby a slight movement of the piston in one cylinder causes the pressure to be transferred to the other piston of said cylinder nd means for applying pressure to said pistons.

8. The combination with a controller for motor circuits of means for operating said controller step by step comprising two cylinders one for each direction of movement 7 each having two istons therein, one piston in one cylinder being rigidly connected with a piston in the other cylinder, means wherebya slight movement. of each piston in a cylinder causes the pressure thereon to be transferred to the other piston of saidcylinder and means for applying pressure to said" pistpns.

9. The combination with a controller for motor circuits of means for ope-ratin said controller step by step comprising a cy inder having two pistons therein each having an opening therethrough and a valve for the opening and means whereby movement of each piston causes the valve therein to open and the valve in the other piston to close.

10. The combination with a controller for motor circuits of means for operating said controller step by step comprising a cylinder having two pistons therein each having an opening therethrough and a valve for the opening and. means whereby movement of one piston causes the valve to open and the pressure to be applied through the opening to the other piston, and,- movement of the other piston causes its valve to open and. the valve of the other piston to close.-

11. The combination with a controller for motor circuits of means for operating said controller step by step comprising a cylinder for each direct-ion of movement and two pistons in each cylinder and means whereby a slight movement of each piston causes the pressure to be transferred to the other piston, a normally open electromagnetic valve for one cylinder, a normally closed electromagnetic valve for the other cylinder and means for energizing said valves simultaneously.

12. The combination with a controller for motor circuits of means for operating said controller step by step comprising a cylinder for each direction of movement and two pistons in each cylinder each piston having an opening therethrough and a valve for the opening, means whereby the movement of one piston causes its valve to open and the pressure to be applied through the opening to the other piston in said cylinder and the movement of the other piston in said cylinder causes its valve toopen and vthe valve in the other piston to close, a normally opened electromagnetic valve for one cylinder and a normally closed electromagnetic valve for the other cylinder and means for energizing said valves simultaneously.

In witness whereof, I have hereunto set m hand.

y FRANK E. CASE. 

